Charcoal briquette and process of making same



Patented Aug. 18, 1925.

4 NI D ATES PATENT orrlcs.

WALTER A. LE'UENBERGER AND WILLIAM T. DUMBLETON, OF TACOMA, WASHINGTON,

- ASSIGNORS T CARBON BRIQUET COMPANY, A CORPORATION OF WASHINGTON.

CHARCOAL BRIQUETTE AND PROCESS OF MAKIllTG SAME.

NcDrawing.

Our inventionrelates to a process for the manufacture of a fuel fiom charcoal in which the product is in the form of a briquette and also to the product itself.

The object-of our invention is to provide a process by which Waste wood orvegetable matter o'f any kind maybe manufacturedi into a fuel of a kind which may be readily stored and handled during transportation and burning, and one'which possesses the physical properties to: enable it to be used as a fuel in the same manner as common fuels such as coal and coke.

Our process consists in the manner of treating waste wood and vegetable products so that they are first carbonized or converted into charcoal and'the charcoal is then put into the form of briquettes. Our invention also consists of the product manufactured by this process.

The manner of carrying out our process and the character of theproduct will be hereinafter described and then defined in the claims.

While many attempts have been made to utilize waste vegetable products as fuel and to manufacture them into briquettes or such form that they may be usedin the same manner as is ordinary coal or coke, it has heretofore been found diflicult, if not impossible, to make from charcoal a fuel which has the physical properties which will enable it to stand up under the firing conditions ordinarily employed with natural fuels such as coal and coke; or if it has been possible to make a briquctte having the proper physical strength and qualities to enable it to stand up under handling, it has either possessed objectionable qualities of some other character or its cost of manufacture has been prohibitive.

.By our process is produced a product which possesses all the strength and physical characteristics necessary to enable it to Application filed December 23, 1922. Serial No. 808,774.

be shipped, handled and burned, in the same apparatus and in the same manner as would e employed for charcoal, coke, coal or any other solid fuel, and at the same time the cost of manufacture is sufiiciently low to enable it to compete with the more ordinary. forms of fuel.

The chief source of material for the manufacture of this fuel would be mill and forest waste products such, for instance, as sawdust, slabs, bar and the like, together with imperfect pieces of wood which are one of the waste products of-a sawmill. The other source of supply might well be the tops and other waste timber which is not considered of any value for lumber purposes and which ordinarily is left upon the ground to rot or is burned up.

The first step in the preparation of such material for our purpose is to get this into shape so that it may be conveniently handled and carbonized. The most practical manner of doing this we believe to be to reduce the The woodproducts', after suitable prepaany other a preciable content, or itmay be in part or w of carbonization or from another source.

of an aqueous liquid. This liquid might be water without olly pyrolig'neous acid orother like byproduct obtained during the process.

Such-pyroligneous acid contains large quan-' v tities of water, or rather, pyroligneou's acid is held insolutionin a large quantity of water and the water content of such a mix ture may answer the purpose for quenching I the charcoal.

We have found that to permitthe charcoal to cool in a natural way or in themannen which has heretofore'been employed, pros duces a condition in the charcoal'which makes it difficult if'not impossible to produce a briquette having the physical characteristics desired. If the charcoal be quenched in the manner stated by the application of an aqueous fluid, the charcoal may ing steps of our process, into a briquette which will have sufficient physical strength to stand any usage to which coal or coke is ordinarily submitted.

When charcoal thus formed is quenched by the application of an aqueous fluid thereto, it will in 'the quenching process ab- 'sorb a considerable percentage by weight of said fluid. This percentage will often run from 10% to 15% of the dry weight of the charcoaL- The next step in the preparation of the charcoal for the manufacture ofl briquettes is grinding. If the percentage of water absorbed in the charcoal by the quenching process is sufficient, the charcoal may be ground without the addition of any other water and also without producing any material or considerable amount of dust. If necessary, however, additional water is added to the charcoal during the process of grinding.

After thorough grinding of the charcoal it is introduced to a mixer and to the mass is added the binder. This binder or the binder which we prefer to use, consists in the main, of a tarry product as, for instance, the tarry products which are given off during the carbonization process or, with this, the product which is obtained from the'second retorting process to which the molded briquettes are subjected, and which will be later described. However, commercial tar obtained from the distillation of coal may be employed if this be desired.

With the tarry ,product is added a small percentage of fuel oil. By fuel oil is meant the heavier or what isordinarily considered as the waste products of the distillation of petroleum. This may be what is ordinarily sold as fuel oil or in some cases, a low grade of crude oil. At the same time, if there be insufficient moisture in the product, water may be added.

The percentage of these various ingredients which are preferably employed by us, Wlll range about as follows. With the Weight of the dry charcoal considered as 100, there will be added to this water to the extent of about 30% of the weight of the dry charcoal. The binder consisting of the tarry contents will be used to the extent of from 15% to 30% of the weight of thecharcoal,

and to this approximately 1%, or in some cases slightly-less, of fuel oil. In figuring the water content the water contained in the binder is to be included.

The amount of fuel oil to be added will vary. The amount may be determined by observation. The addition of the Oil tothe be converted by the use of the remainmass should be sufficient to give it a coloration which may be described asblue-black, as distinguished from a dead-black. In other words, the coloration is suggestive of the oily sheen observed on water which has a film of. oil thereon. More than enough to bring out this coloration is unnecessary and generally, injurious.

We find that the addition of too much of the fuel oil to the paste has an injurious effect on the physical characteristics of the briquettes made therefrom. Such briquettes do not have the strength and the ability to stand up under rough handling and burning.

When, however, the amount of oil added is being molded are then placed within a closed chamber or retort where they are heated. to a temperature which may vary from 250 to 600 F. The temperature to which the briquettes are subjected will vary in accordance with the physical characteristics desired in the finished product.

If the briquettes are subjected only to the lower ranges of temperatures, as, for instance, in the neighborhood of 300 F., during this second retorting, they do not possess as much strength and ability to stand rough handling or the ability to resist the load of a heavy fire, as, for instance, in a blast furnace, as they would if subjected to a higher temperature during this retorting. We have found from practice that briquettes made in this way are capable of resisting a crushing force of from 100 pounds to 600 pounds per square inch. To obtain the higher resisting capacity it is necessary to subject them to higher temperature in this second retorting process. Where, however, the use to which they are to be put does not need such physical strength, retorting at a lower temperature is permissible.

The blue-black coloration or the sheen effect heretofore referred to, persists in the briquette and is still found on the finished product. After the briquettes have been subjected to this second retorting action they are cooled in an oxygen free atmosphere, as unless this be done their temperature might cause ignition. This may be done in the retort, or preferably by transferring them to "a chamber which may be closed and charged be the important or critical steps therein. First, is the quenching of the charcoal when first made by the application'thereto of an aqueous liquid. Associated with this is the incorporation of a considerable percentage ofwater 1n the ground charcoal at the time it is worked into the pasty condition for briquetting. The other critical point is the use of the proper proportion of fuel oil and the second retorting. As before stated, too much fuel oil is objectionable. The desired percentage is, as before stated, about 1% of the weight of the dry charcoal or in some cases somewhat less than this.

\Ve have found it possible to manufacture briquettes of this kind at a price which will enable them to compete with coke or coal at their market prices. The fuel quality of these briquettes is equal to that of coke or anthracite coal. They have a very small percentage of ash and also a very small percentage of water in the finished product. The considerable percentage of water contained in the briquettes when molded, is driven off during the second retorting. Also the volatile products contained in the binder is also driven ofl' during this retorting and may be recovered as a by-product or for use in forming a binder for other charges of charcoal. Briquettes made in this manner may be handled Without soiling the hands. They are hard and may be handled fortransportation and firing in the same manner as anthracite coal Without breaking up. V Furthermore, they are substantially impervious to the action of water. While they will absorb a very small, percentage of moisture, chemical analysis of briquettes which have been submerged under water for a considerable time, show only from 1% to 2% of moisture. As a fuel they are believed to be equal in every respect to anthracite coal. a

What we claim as our invention is:

1. The step in the manufacture of fuel briquettes from charcoal which consists in heating the briquettes after molding the same from previously formed charcoal to a temperature varying from 250 F. to 600 F. in accordance with the hardness desired in the final product.

2. The herein described process of briquetting vegetable matter for use as a fuel which consists of distilling the vege table matter' in a retort to convert it into a charcoal, quenching'the hot charcoal from the retort by a fluid consistingprincipally of water, adding a binder, molding the charbriquetting vegetable matter'whichconsists of distilling the vegetable matter in a retort to convert it into charcoal, quenching the hot charcoal from the retort by a fluid consisting principally of water, molding the charcoal into briquettes and heating said briquettes after molding.

4. The process of briquetting charcoal for use as a fuel which consists in giving the charcoal a percentage of absorbed water sufiicient to substantially prevent formation of dust when grinding, grinding such charcoal, mixing therewith a binder, molding and then heating the briquettes to drive off the moisture and a part of the volatile contents.

5. The process of briquetting charcoal for use as a fuel which consists in giving the charcoal a percentage of absorbed water sufiicient to substantially prevent the formation of dust when grinding, grinding such charcoal, mixing therewith a binder, molding and then heating the briquettes in an oxygen-free atmosphere.

6. The processof briquetting charcoal for use as a fuel which consists in the aqueous quenching of the charcoal after retorting, grinding the charcoal,adding thereto sufficient water to give a total content of approximately 30% of the dry Weight of charcoal, from 15% to 30% of a tarry distillate, and 1% of fuel oil, mixing and molding the compound, and heating the briquettes to a temperature varying from 250 F. to 600 F. in accordance with the hardness of the briquettes desired.

7. The step in the process of briquetting" drive offthe moisture content and at a tem-' perature which also drives off "a material part of the volatile contents of the binder used.

8. The process of briquetting charcoal for use as a fuel which consists in the aqueous quenching of the charcoal, grinding the charcoal, adding thereto Water,,tarry distillates and a limited percentage of fuel oil and mixing the whole, molding the products and heating the briquettes to drive off the desired percentage of its moisture and volatile contents.

9. The process of briquetting charcoal for use as a fuel which consists in the aqueous quenching of the charcoal, grinding the charcoal, adding thereto water sufficient to total approximately 30% by weight of the dry charcoal, tarry distillates and a limited amount of fuel oil as abinder, molding the briquettes and finally heating the briquettes to drive ofl" substantially all of the water volatile content of such fuel oil having been a briquette made with a volatile carbonadriven off by the application of heat to the briquettes after the molding of the same from previously formed charcoal.

11. A fuel briquette made of vegetable ceous binding material.

13. A fuel briquette made of vegetable charcoal having its charcoal particles bound together by a heat-hardened carbonaceous film formed in place.

14. A fuel briquette made of vegetable charcoal having its charcoal particles bound together by films of hard and relatively water roof material formed in place by subjecting briquettes having a tarry binder to the action of heat after molding.

15. A composition of matter constituting a briquette and consisting ofvegetable charcoal and a plastic binder which binder has been converted into a solidwaterproof film by heating the briquettes after their formation from previously made charcoal.

16. A composition of matter constituting a briquette and consisting of vegetable charcoal and a binder the latter having a moisture and gas proof character when cold and the pores and interstices of the briquette being free of material capable of becoming disruptive when heated.

17. A composition of matter constituting a briquette and consisting of vegetable charcoal and a binder which binder when heated becomes sufficiently plastic to permit passage heated of vapors and gases with restoration of its integrity when cooled and when cooled is substantially impervious to the passage of gases and vapors, the briquette having been after formation to thereby expel heat-vaporizable materials therefrom and to harden the same.

18. The hereindescribed process of forming a briquette which consists of combining preformed vegetable charcoal and a binder and heating the whole to render the binder sufficiently plastic to permit the passage of vapor and gases and to drive the moisture heating the from the pores of the charcoal through said binder, said binder having its integrity restored when cooled and when cooled being substantially impervious to the passage of gases and vapor and being highly resistant to the passage of moisture whereby the reentry of moisture to the pores of the charcoal is prevented.

19. The hereindescribed process of manufacturing a fuel briquette which consists of mixing preformed charcoal and a binder adapted to be rendered plastic when heated,

whole to render the binder plastic and to drive off the contained moisture from the pores of the charcoal to thereby render the briquette free from vaporizable disruptive material when burned, molding the material into briquette form and heating I the same after formation of the briquette to convert the binder into a hard, tough insoluble and highly waterproof film.

20. The hereindescribed step in the process of forming fuel briquette of charcoal which consists of filling the pores of the charcoal with a binder excluding liquid, mixing the charcoal with the binder and heating the whole to drive'the binder excluding material from the pores of charcoal and outwardly through the binder whereby the pores and interstices of the charcoal are rendered free of moisture likely to become disruptive when the briquette is burned.

21. The hereindescribed step in the process of forming fuel briquette of charcoal which consists of filling the poresof the charcoal with a binder excluding liquid, mixing the charcoal with the binder and heating the whole to drive the binder excluding material from the pores of charcoal and outwardly through the binder whereby the pores and interstices of the charcoal are rendered free of moisture likely to become disruptive when the briquette is burned, and heating the briquette after molding to render the binder hard, tough and water-proof so that the pores of the charcoal Wlll be maintained free of moisture, capable of becoming disruptive when the briquettes are burned.

Signed at Seattle, King County, Washington this 18th day of December 1922. 

